Catheterization of a body cavity is frequently performed in medical procedures either to insert substances into or to remove substances from the body. During many of these procedures, it is necessary to keep the catheter in a relatively stable position to perform the desired insertion or removal. With the use of enteral feeding catheters (i.e., catheters which enable the administration of nutritional solutions directly into the stomach or intestines), for example, it is necessary to ensure that the catheter is not accidentally removed from the stomach or intestines. This is true both during the actual administration or removal of fluids, and the time periods in between.
In order to ensure that a catheter is maintained in the proper position, i.e. not accidentally removed or displaced, it is common to use a balloon disposed near the distal (patient) end of the catheter shaft. Inflating the balloon causes the balloon to contact the anatomical structure (i.e., a duct or stomach wall) and thereby prevents the catheter from moving out of the proper position. In the case of enteral feeding, a stoma is formed leading into the stomach or intestine. The catheter is positioned to extend through the stoma so as to form a channel into the stomach or intestines through which enteral feeding solutions may be instilled. Depending on the type of catheter, the balloon may be positioned in a variety of locations along the catheter shaft. For example, with a G-tube the balloon will generally be at or near the distal end of the catheter, although the balloon or other retention mechanism may be slightly closer to the head of the catheter provided that the retention effect may still be achieved.
FIG. 1 shows a side view of a prior art balloon catheter 10 (available from Ross Products Division of Abbott Laboratories, having offices in Abbott Park, Ill.) having a head 14 disposed at a proximal end 15 of the catheter 10. The head 14 contains valves (not shown) which regulate the flow of fluids through the balloon catheter 10. The head 14 also prevents the balloon catheter 10 from completely advancing through the stoma (not shown) and into the stomach or intestine of the user.
To prevent the catheter 10 from being pulled out of the stomach/intestinal wall, a balloon 18 is disposed along a catheter shaft 26. The catheter 10 is shown having an optional stiff tip 30, which is attached to the catheter shaft 26 at a distal end 17 opposite the head 14. The catheter shaft 26 is typically made of a medical grade silicone. The stiff tip 30, when present, is also frequently formed of a medical grade silicone but is usually configured to be as rigid as or less rigid than the catheter shaft 26.
The balloon 18 is advantageous because it allows the catheter shaft 26 to be inserted into the stoma (not shown) while the balloon 18 is uninflated. Once the catheter shaft 26 is properly positioned in the stoma, a syringe (not shown) is inserted into a side port 36 of the head 14 and a fluid is injected into the balloon 18 through a lumen (not shown in FIG. 1) of the catheter 10 so as to inflate the balloon 18.
While the balloon 18 remains inflated, the catheter 10 stays properly positioned in the stoma. The position of the balloon catheter 10 is maintained in such a manner until removal is desired. If the catheter 10 needs to be removed, the balloon 18 may be deflated so that it will not interfere with withdrawal of the catheter shaft 26.
The type of balloon 18 shown in FIG. 1 is fashioned around the perimeter of the catheter shaft 26 such that when it is deflated it reduces or contracts about the shaft 26. Although the balloon 18 will generally reduce or contract about the shaft 26, the balloon 18 clearly adds size to the portion of the catheter 10 which it surrounds.
Attachment of the balloon 18 to the catheter shaft 26 is frequently accomplished by gluing the balloon proximal end 20 and the balloon distal end 22 to corresponding positions on the external surface of the catheter shaft 26 so as to form a proximal cuff 32 and a distal cuff 34, respectively. Such cuffs 32 and 34 are longitudinal sections of the balloon 18 whose inside diameters correspond to the outside diameter of the shaft 26 at their respective points of attachment to the catheter 10 and have a distance between them which is about the length of the uninflated balloon 18. The cuffs 32 and 34 must be of sufficient length to provide a tight and durable seal between the balloon 18 and the catheter shaft 26.
While the prior art balloon configuration shown in FIG. 1 works to maintain the balloon catheter 10 in the proper position within the patient, balloon catheters of this type as well as the other known balloon catheters do have disadvantages. For example, one drawback of prior balloon catheters is discomfort to the user. With regard to the catheter of FIG. 1, in order to allow insertion of the catheter 10, the catheter shaft 26 and especially the stiff tip 30 must be relatively rigid or firm to prevent buckling under insertion pressures. However, this same firmness makes the distal tip 30 much more prone to irritate anatomical structures which come into contact with it. This is especially true in the stomach and intestines where the opposing walls of the anatomical structures tend to collapse on each other during physical exertion or when the cavity has little or no food. As the person moves, the stiff tip 30 repeatedly engages the adjacent anatomical structure (such as the stomach wall) and can lead to irritation and/or discomfort for the user. Thus, as the presence of an extended stiff catheter tip in this environment has been suspected of irritating the opposing surfaces of the body cavity, it would be desirable if the patient could be protected from exposure to the tip 30.
Accordingly, there is a need in the art for a balloon catheter with a distal tip which may be isolated from opposing internal body cavity surfaces.
Another disadvantage with the prior art balloons of the type discussed above, is that if they were to be secured to the interior portion of the tip 30 they would provide undesirable restriction of the flow of fluids therethrough. Although not done in prior catheters, if the tip were to be attached to the interior of the catheter shaft, the flow would be further reduced. The reduction in flow can result in the need for longer use of the catheter to obtain the desired level of fluid flow. If a catheter having a wider tip or shaft is used to overcome the fluid flow issue, the stoma through which the catheter must be inserted will need to be larger thereby creating other issues, such as increased time for the stoma to heal as well as creating a larger opening through which fluids can leak out.
Accordingly, there is a need for a catheter which can provide for an increased level of fluid flow (as compared with prior devices) without the need for a larger stoma opening.
Yet another disadvantage with prior art catheters of the type discussed above is that they generally first require the separate manufacture of multiple pieces (e.g., the catheter, the rigid tip and the balloon), then the attachment of the tip to the catheter and one end of the balloon and, finally, the attachment of the second end of the balloon to the catheter. Each of the attachments methods have been done manually in the past. Naturally, this manual operation is slow, costly and inefficient. Further with each additional step in a process there exists an opportunity for error and waste of product. To avoid the additional production and assembly steps, in many prior catheters the balloon is attached directly to the outside of the catheter without a tip; however, catheters of this sort do not enjoy the benefits the tips may have to offer.
Thus, while there is a need for catheters, because of the number of individual pieces or members which comprise a catheter and because those pieces are typically assembled by hand or at least in multiple assembly steps, there is a need in the art for a catheter which requires less assembly, and specifically less manual assembly.